Abstract: Cu₂O spherulites with different morphologies, such as three-dimensional cruciform, hollow and solid Cu₂O spherulites were prepared under DMF solvothermal conditions by changing copper source, surfactant and reaction parameters.The products were characterized by XRD and SEM, and the influences of process conditions on the morphology of Cu₂O spherulites were analyzed. The results indicate that with the increase of DMF concentration, the reduction capacity of the system is enlarged, Cu⁺ increases, and the solution supersaturation is enhanced. The spherulites with anisotropy and symmetry controlled by the crystal structure of Cu₂O crystal aggregates gradually evolve to isotropic spherulites. Surfactants such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), and polyvinylpyrrolidone (PVP) are beneficial to reduce the supersaturation of the solution, the surface diffusion ability of the crystalline substance is improved. And the formation of Cu₂O grains tends to be regular. In the reaction system, the carboxyl group generated by the hydrolysis of Cu(Ac)₂·H₂O and the formyl group in DMF undergo decarboxylation reaction at high temperature to generate CO₂ gas and the gas generated by SDS foaming is an important reason for the formation of hollow Cu₂O spherulites.

Key words: Cu₂O, spherulite, solvothermal method, DMF, supersaturation of solution